It was a hectic Monday morning for Peter Mandelson, who was packing up his home before heading to Buckingham Palace for an audience with King Charles III, on the eve of becoming Britain’s ambassador to the United States.
But the stress of leaving London may not compare to what awaits Mr. Mandelson when he lands in Washington on Wednesday. Few British diplomats have taken on a job as fraught with political risk as Mr. Mandelson’s. His first day at the embassy will coincide with President Trump’s 18th day in the Oval Office — and already, some of America’s sturdiest alliances are teetering.
As he packed boxes, Mr. Mandelson was keeping an eye on Mr. Trump’s latest exchanges with Canada and Mexico, after he had imposed — then paused — sweeping tariffs. The European Union looked to be next in his cross hairs. Mr. Trump was gentler about Britain, suggesting to reporters that a deal “could be worked out,” though he claimed its trade balance with the United States was “way out of line.”
“I’m not going to tell the president his business when it comes to trade,” Mr. Mandelson said in an interview, striking a scrupulously diplomatic tone. But he insisted, “We have a balanced trade relationship with the U.S. It’s balanced in goods; it’s balanced in services.”
For Mr. Mandelson, the trick will be to keep Britain out of Mr. Trump’s line of fire — and to do it at a time when Prime Minister Keir Starmer’s left-of-center government is trying to reset its relationship with the E.U., to which Mr. Trump has long been hostile.
Mr. Mandelson has already been denounced by a faction of Trump loyalists, who failed to scuttle his nomination but may have played into his decision to apologize on Fox News last week for deriding Mr. Trump during his first term as a “white nationalist” and a “danger to the world.”
Mr. Mandelson knows the ins and outs of trade flows: He served as the European Union’s trade commissioner from 2004 to 2008, and then headed Britain’s Board of Trade until 2010. He said he hoped his experience would help him make a persuasive case on behalf of Britain, which runs either an $89 billion trade surplus or a $14.5 billion deficit with the United States, depending on whether one cites British or American statistics. (The difference rests in part on how the two sides treat offshore financial centers like Jersey and Guernsey, which are crown dependencies.)
“If I can use that knowledge to advance some mutual understanding, I will do so,” he said. Still, he was quick to add, “I’m not going to be front-of-house in making arguments against the president’s policies. My job is to act behind the scenes to explain our countries’ policies to each other.”
Such a low profile makes sense in Mr. Trump’s Washington, given the president’s history of clashing with big personalities. But it is out of character for Mr. Mandelson. In a four-decade political career, he thrust himself repeatedly into the spotlight. As a young strategist for the Labour Party, he was known for his ruthless tactics, earning the nickname the Prince of Darkness.
Since then, Mr. Mandelson, 71, has fallen in and out of favor with successive Labour leaders, from Tony Blair, for whom he was once a trusted adviser, to Mr. Starmer, to whom he became close before his election victory last July.
Mr. Starmer’s decision to appoint Mr. Mandelson to a post as sensitive as ambassador to the United States surprised some in London, given the prime minister’s reputation for caution and Mr. Mandelson’s reputation for swagger and sharp elbows.
A few of those elbows were thrown at Mr. Trump. In addition to his comments in a 2019 interview with an Italian journalist, Mr. Mandelson wrote a column in 2018 for a London paper, The Evening Standard, in which he took Mr. Trump to task for imposing tariffs on China. The president, he wrote, was a “bully and a mercantilist.”
Mr. Mandelson said, “I completely stand by the intellectual argument” about the negative effect of tariffs. But he said he regretted his choice of words about Mr. Trump. He chalked it up to the inflamed atmosphere in Britain, which was then negotiating its exit from the European Union.
“In 2019, I was a bit irate,” he said. “But nonetheless, the words I used about the president were childish and wrong.”
Mr. Mandelson is also under pressure because he is replacing Karen Pierce, a popular envoy known for having built bridges to people in Mr. Trump’s orbit. When his appointment was announced in December, Chris LaCivita, a Republican strategist who comanaged Mr. Trump’s campaign, posted, “replace a professional universally respected Ambo with an absolute moron — he should stay home!”
Among his other critics were Stephen K. Bannon, Mr. Trump’s former chief strategist, and Raheem Kassam, the British-born former editor of Breitbart News in London. Mr. Bannon said he had objected to Mr. Mandelson’s business dealings in China, while Mr. Kassam said he was “Tony Blair’s most effective operator,” which he did not mean as a compliment.
“Whether it’s a rejection of his credentials, or bringing him to heel, it’s a victory,” Mr. Kassam said of the campaign against him.
Still, Mr. Mandelson drew no public opposition from other powerful Trump allies, like the technology billionaire Elon Musk, or hawkish Republicans like Secretary of State Marco Rubio. He would hardly be the first person who once denigrated Trump to win forgiveness.
Mr. Mandelson emphasized his ties to Silicon Valley, which he visited as a minister in 1998 to draw up a white paper on Britain’s competitiveness. He said his experience in China, which deepened during years of running a consulting firm, Global Counsel, would help him nurture joint British and American competition with China.
“Our chief goal must be to win the advanced technology race,” he said. “We can only win that race together, not divided.”
Mr. Mandelson’s defenders say his heavyweight credentials and cosmopolitan manner could appeal to Mr. Trump, who may recognize in him a fellow player. While they do not know each other, they have moved in similar social circles. Mr. Mandelson sits in the House of Lords, the kind of sinecure that Mr. Trump might also appreciate.
“London will be hoping that assigning a political figure of Mandelson’s stature and intellect will be seen as a compliment, and his experience of trade policy in Brussels not an impediment but an asset,” said Peter Westmacott, who was ambassador during the Obama administration.
Kim Darroch, who served as ambassador during Mr. Trump’s first term, said, “I suspect he’s taken this job because he’s addicted to the political game, and this is a way back on to the field. He’s relentlessly engaged in it, relentlessly curious about it, and exceptionally good at it.”
Mr. Darroch, however, offers a lesson in the perils of diplomacy during a Trump presidency. He was forced to resign in 2019 after a London paper published confidential cables in which he offered an unfiltered, unflattering take on the president.
Mr. Mandelson will try to avoid those traps, in part by playing to Mr. Trump as a deal maker. He rejected suggestions that Britain needed to choose between the United States and Europe. Britain, he said, was merely trying to “tidy up” a flawed trade deal negotiated by Mr. Starmer’s Conservative predecessors.
“What we want with the E.U. is complementary to the U.S.,” he said.
“We got a bad deal with the E.U.,” he added. “The president understands what a bad deal looks like.”
